Method and system for cleaning sand

ABSTRACT

One or more techniques and/or systems are disclosed for producing beneficial re-use sand from foundry sand. Foundry sand can be collected from a mold making operation, and/or from the casting removal and cleaning process. The collected sand product can be cleaned and separated into a clay and carbon mixture, and a beneficial re-use sand. The collected sand product can be cleaned by mixing with water, and subjecting the resulting mix to a hydrocyclone at appropriate flow rates. The hydrocyclone can separate the mix into a carbon, clay and water mix for re-use, and a wet sand mix. Water can be separated from the wet sand and reused, and the resulting sand can be used as beneficial re-use sand.

This application claims priority to U.S. Ser. No. 62/463,235, entitledMETHOD AND SYSTEM FOR CLEANING SAND, filed Feb. 24, 2017, which isincorporated herein by reference

BACKGROUND

Foundry operations utilize green sand to create molds for casting metalproducts. The green sand typically comprises a mixture of sand, a bindermaterial (e.g., clay and carbon mix), and water. The molds are formed,the casting is made, and the used sand is removed from the casting. Theresulting used sand can be disposed of, or portions may be re-used afterbeing subjected to specialized treatment. Re-using sand products from afoundry can potentially save resources for a foundry. However, theeffective collection and treatment of high-quality re-use sand oftenutilizes specialized processes and systems.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key factors oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

As provided herein, one or more methods and systems for cleaning a sandproduct from a foundry sand handling operation is provided. Foundry sandcan be collected from a variety of places in a foundry, including a moldmaking operation, and/or a casting removal and cleaning process. Thecollected sand product can be cleaned and separated into a clay andcarbon mixture, and a beneficial re-use sand. The clay and carbonmixture may be re-used in the foundry, and the beneficial re-use sandcan be used offsite.

In one implementation, a method for producing beneficial re-use sandfrom foundry sand can comprise mixing water with a sand product at anapproximate ratio of two-parts water to one part sand product, resultingin a sand product/water mix. The sand product can be received from afoundry bag-house collector or from spent foundry sand. Further, aclay-carbon and water mix can be extracted from the sand product/watermix, where the clay-carbon and water mix re-used in a foundry.Additionally, wet sand can be extracted from the sand product/water mix.The wet sand can be separated into a water stream and a sand stream. Inthis implementation, the water stream can be used as at least a portionof the water in the water and sand product mixing. The sand stream fromthe separation can comprise the resulting beneficial re-use sand.

To the accomplishment of the foregoing and related ends, the followingdescription and annexed drawings set forth certain illustrative aspectsand implementations. These are indicative of but a few of the variousways in which one or more aspects may be employed. Other aspects,advantages and novel features of the disclosure will become apparentfrom the following detailed description when considered in conjunctionwith the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

What is disclosed herein may take physical form in certain parts andarrangement of parts, and will be described in detail in thisspecification and illustrated in the accompanying drawings which form apart hereof and wherein:

FIG. 1 is a schematic diagram illustrating an implementation of anexemplary system for producing beneficial re-use sand.

DETAILED DESCRIPTION

The claimed subject matter is now described with reference to thedrawings, wherein like reference numerals are generally used to refer tolike elements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the claimed subject matter. It may beevident, however, that the claimed subject matter may be practicedwithout these specific details. In other instances, structures anddevices may be shown in block diagram form in order to facilitatedescribing the claimed subject matter.

Beneficial re-use foundry sand has found use in a variety ofapplications and industries. Further, beneficial re-use foundry sand canbe a commodity instead of a waste product, potentially saving resourcesfor a foundry. Beneficial re-use foundry sand comprises sand that hasbeen used by the foundry and typically may not be appropriate for re-useby the foundry. Effective collection of high-quality re-use sand mayutilize specialized processes and systems.

A system can be devised that can produce high quality beneficial re-usesand, from a foundry. In one example implementation, as illustrated inFIG. 1, a system for producing beneficial re-use sand can comprise amixer. The mixer can be configured to mix water and a sand product,resulting in a sand product/water mix. As an example, the mixer may beconfigured to continually (e.g., as a continual or intermittent steam,at least while in operation) receive a supply of water and a supply sandproduct, and continually mix these ingredients to produce a continualflow (e.g., as a continual or intermittent steam) of the sandproduct/water mix. In one example, the water and sand product may bereceived at a top area of the mixer, and the sand product/water mix maybe discharged from a bottom portion of the mixer.

In one implementation, the water and sand product may be introduced tothe mixer at an approximate ratio of about three-parts water to one partsand product or less. The ratio may be about two-parts water to one partsand product. As an example, for respective batches of the sandproduct/water mix, approximately sixty pounds of the sand product may beintroduced to the mixer, along with approximately one-hundred eightypounds of water. As another example, for respective batches of the sandproduct/water mix, approximately sixty pounds of the sand product may beintroduced to the mixer, along with approximately one-hundred twentypounds of water. As another example, the specific ratio of water to sandproduct may be altered to provide a desired sand product/water mix,depending on the type of sand product that is used for the mix, and thetype and specifications of the mixer used, along with the specificationsfor the other parts of the system.

In one implementation, the sand product may comprise a material that iscollected from a foundry bag-house collection system. That is, forexample, during foundry sand handling procedures, such as separation ofthe castings from the molds, handling and reconditioning of the usedsand during shake-out or knock-out, mechanical and pneumatic conveying,bucket elevators, mixers and sand coolers, as well as cast cleaning,foundries often employ dust collection equipment to collect the airborneparticulate released during these procedures. In this implementation,the collected sand product (e.g., dust and other collected material) canbe used as the sand product in the example methods and systems describedherein. As one example, the sand product collected from the dustcollection systems may comprise approximately fifty percent (50%) sandand approximately fifty percent (50%) clay and carbon mixture. In onenon-limiting example, the clay may be a bentonite clay.

In another implementation, the sand product may comprise used sand thatis collected from spent foundry sand. As an example, green sand is usedfor to create the molds for cast products, and after the casting iscreated, the mold sand can be collected as used or spent foundry sand.Further, during the mold creation process, excess sand may be generatedduring the mold creation process, which can also be collected. In thisexample, these types of used foundry sand can comprise the sand productin the example methods and systems described herein. As one example, thesand product collected from the used or spent foundry sand may compriseapproximately the same constituent make-up as green sand used to makethe molds.

As illustrated in FIG. 1, the water and dust or sand can be mixed in amixing vessel, such as by using a mixing blade, vessel agitation, and/orvessel rotation, but not limited thereto. Further, in oneimplementation, the mixing may occur as a batch process, where theingredients are added and mixed appropriately, resulting in a batch ofthe water and sand product mix. In another implementation, the mixingmay occur as a continuous process. In this implementation, theingredients can be continuously (e.g., intermittently or in a continuousflow) added to the mixing vessel in the desired proportions (e.g., about3:1 or less of water to sand product), for example, at a top area of thevessel. Additionally, in this implementation, a resulting desiredmixture of the water and sand product may be continuously (e.g.,intermittently or in a continuous flow) drawn from the vessel, forexample, at a bottom area of the vessel.

As illustrated in FIG. 1, the resulting sand/water mix can be introducedto a hydrocyclone system. For example, a hydrocyclone can be used toseparate or sort particles in a liquid based on their fluid resistance.In this example, denser or courser particles (e.g., sand) typically havea higher fluid resistance to a generated centripetal force than the lessdense or finer particles (e.g., clay, carbon), as well as water. Thatis, for example, the sand or dust and water mix can be pumped into thehydrocyclone at a desired pressure (e.g., thirty pounds of pressure persquare inch (PSI) or more) to generate a desired centripetal forceinside the hydrocyclone. In this example, because the sand is courserand denser than the clay and or carbon found in recovered sand product,wet sand can be separated from a clay, carbon and water mix. Typically,the denser and/or courser material is retrieved from a bottom of thehydrocyclone, and the lighter and/or finer material can be drawn from atop portion of the hydrocyclone.

As an illustrative example, when a desired sand product and watermixture is introduced to the hydrocyclone at a desired flow rate, aresulting separation of the sand from the clay and carbon mix produces adesirable product. For example, the mixing of the water to sand productat a ratio of approximately two parts water to one part sand productproduces a desirable product when introduced to the hydrocyclone at apressure of thirty PSI or more (e.g., up to fifty-five PSI). In thisexample, the wet sand product and the clay, carbon and water mix productrecovered from the hydrocyclone comprises desirable properties forfurther use (e.g., beneficial re-use sand, and clay, carbon, water mixfor foundry use). That is, in one implementation, the mixing of the sandproduct and water at the desired amount and rate, as described herein,in combination with introduction of the sand product and water mixtureinto the hydrocyclone at the desired pressure, as described herein, mayallow passing the mixture through the hydrocyclone separation processmerely the one time, for example, instead of multiple passes through ahydro separation process to obtain the desired separate products.

In one implementation, the clay, carbon and water mix that is collectedfrom the hydrocyclone contains approximately ten to eighteen percent(10-18%) solids, with the remaining portion comprising water. Further,in one implementation, typical makeup of the collected solids cancomprise approximately seventy percent (70%) clay and thirty percent(30%) carbon; however, this makeup will be dependent upon the dust orsand input to the mixing portion of the example method or system, alongwith the setup of the hydrocyclone.

In one implementation, the clay, carbon and water mix can be drawn fromthe hydrocyclone, and collected, such as in a collection vessel orstorage area. In one implementation, the collected clay, carbon andwater mix may be returned to the foundry, and reused in the green sandmolding process. For example, foundry sand reclamation systems oftenutilize a sand cooler, which is used to cool the reclaimed sand forre-use (e.g., in a mulling portion). In this example, sand coolerstypically introduce water to help cool and temper the sand, and even outtemperature spots in the sand. As one example, the water may be, atleast partially, substituted with the clay, carbon and water mixcollected from the hydrocyclone, and mixed with the reclaimed sand inthe cooler.

As another example, foundry sand reclamation systems utilize a muller,which may be used to appropriately mix sand with the clay, carbon andwater products, resulting in a green sand product with desirable moldingproperties. In one implementation, the collected clay, carbon and watermix can be introduced to the green sand production process at themulling step. That is, for example, water typically used in the mullermay be, at least partially, substituted with the clay, carbon and watermix collected from the hydrocyclone, and mixed with the sand in themuller. Mulling can be performed in batches or as a continuous process.It should be understood that in other implementations, the clay andcarbon mix may be introduced at any appropriate point in the method ofsystem, including without limitation, a cooler, or the return sandsystem.

In one example, approximately ten gallons of the clay, carbon and watermix collected from the hydrocyclone can be added to a batch of greensand in the muller, or prior to the molding process without additionalmulling. As an example, because the clay, carbon and water mix collectedfrom the hydrocyclone already comprises the products needed to makegreen sand (e.g., other than sand), the mix may be added to the sandsystem prior to molding, such as, for example, using ten gallons of themix with two gallons of thickener, and run though about twenty cycles.The resulting mixture, in this example, is a hydrated and activatedgreen sand, which may not need to be further mulled. In some situations,additional sand may need to be added to make up for any loss during theuse and/or collection process. Overall, utilizing this exampleimplementation, less raw materials are required yielding greater costsavings.

In one implementation, the wet sand drawn from the hydrocyclone may beintroduced to a separator that is configured to further separate remnantwater from the wet sand. That is, for example, the hydrocycloneseparates most of the water from the sand, as the water is included withthe clay, carbon and water mix (e.g., thereby increasing the amount ofwater mixed with the clay and carbon in the reclaimed sand/dust). As anexample, the separator can comprise any system suitable for performingthe function of separating water from the wet sand, such as those thatare commercially available. Further, as an example, depending on anamount of moisture content desired for a resulting beneficial re-usesand, a dryer may be utilized to bring the moisture content to a desiredlevel.

In one implementation, as illustrated in FIG. 1, the water separatedfrom the wet sand may be introduced into the sand product and watermixing step or system. As an example, at least a portion of the waterused in the mixing step may comprise water collected from the separatingstep or separator. Further, as an example, beneficial re-use sand can becollected from the separator. For example, beneficial re-use sandtypically finds other uses that may not be related to foundryoperations. In this example, the beneficial re-use sand can be collectedand transported (e.g., or stored) off-site. In one implementation, there-use sand produced by the methods and systems described herein mayhave a desired make-up, depending on the target use of the producedsand. For example, certain uses may benefit from a re-use sand with alower clay content. In this example, the pressure of the sand productand water mix introduced into the hydrocyclone may be approximatelyfifty to fifty-five psi. In this way, for example, the increasedpressure in the hydrocyclone may provide for removal of more clay fromthe sand mix, resulting in a beneficial re-use sand with a lower clayconstituent. In one example, if enough clay is removed from the sand,the resulting re-use sand may be introduced back into the foundry, inthe green sand production process.

The word “exemplary” is used herein to mean serving as an example,instance or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as advantageous overother aspects or designs. Rather, use of the word exemplary is intendedto present concepts in a concrete fashion. As used in this application,the term “or” is intended to mean an inclusive “or” rather than anexclusive “or.” That is, unless specified otherwise, or clear fromcontext, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. Further, at least one of A and B and/or thelike generally means A or B or both A and B. In addition, the articles“a” and “an” as used in this application and the appended claims maygenerally be construed to mean “one or more” unless specified otherwiseor clear from context to be directed to a singular form.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims. Reference throughout thisspecification to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Of course, those skilled in the art willrecognize many modifications may be made to this configuration withoutdeparting from the scope or spirit of the claimed subject matter.

In addition, while a particular feature of the disclosure may have beendisclosed with respect to only one of several implementations, suchfeature may be combined with one or more other features of the otherimplementations as may be desired and advantageous for any given orparticular application. Furthermore, to the extent that the terms“includes,” “having,” “has,” “with,” or variants thereof are used ineither the detailed description or the claims, such terms are intendedto be inclusive in a manner similar to the term “comprising.”

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary implementations of thedisclosure.

What is claimed is:
 1. A method for producing beneficial re-use sandfrom foundry sand, comprising: mixing water with a sand product,resulting in a sand product/water mix, the sand product received from afoundry bag-house collector or from spent foundry sand; extracting aclay-carbon and water mix from the sand product/water mix, theclay-carbon and water mix re-used in a foundry; extracting wet sand fromthe sand product/water mix; separating the wet sand into a water streamand a sand stream, the water stream used as at least a portion of thewater in the water and sand product mixing, and the sand streamcomprising beneficial re-use sand.
 2. The method of claim 1, furthercomprising the step of introducing the sand product/water mix to ahydrocyclone at about 30 psi.
 3. The method of claim 1, furthercomprising the step of introducing the sand product/water mix to ahydrocyclone at about 35 psi.
 4. The method of claim 1, comprisingmixing water with a sand product at an approximate ratio of aboutthree-parts water to one part sand product or a smaller ratio of waterto sand product.
 5. The method of claim 1, wherein extracting of theclay-carbon and water mix from the sand product/water mix and extractingwet sand from the sand product/water mix occurs through a single passthrough a hydrocyclone.
 6. The method of claim 5, mixing water with asand product to a mixer, further comprising adding the furthercomprising the step of introducing the sand product/water mix to ahydrocyclone at about 35 psi.
 7. The method of claim 1, wherein theextracted clay-carbon water mix contains about ten to about eighteenpercent solids, with the remaining portion comprising water.
 8. Themethod of claim 7, wherein the about ten to about eighteen percentsolids further comprises about seventy percent clay and about thirtypercent carbon.
 9. The method of claim 1, further comprising the stepsof: adding about ten gallons of the clay-carbon and water mix from ahydrocyclone to green sand in a muller; adding about two gallons ofthickener to the about ten gallons of the clay-carbon water mix; andproducing a hydrated and activated green sand.
 10. The method of claim9, further comprising the steps of adding additional sand and/or resinsto the hydrated and activated green sand.
 11. The method of claim 1,further comprising using the beneficial re-use sand for non-foundry use.12. The method of claim 1, further comprising the step of at leastpartially removing moisture from the beneficial reuse sand.
 13. A systemfor producing beneficial re-use sand from foundry sand, comprising: amixer that mixes water and a sand product at an approximate ratio ofthree-parts water to one part sand product or less, resulting in a sandproduct/water mix, the sand product received from a foundry bag-housecollector or from spent foundry sand; a hydrocyclone into which the sandproduct/water mix is introduced at a pressure between about 30 psi andabout 35 psi, the hydrocyclone separating the sand product/water mixinto: a clay-carbon and water mix that is re-used in a foundry, and; awet sand; a separator that separates the wet sand into a water streamand a sand stream, the water stream used in the mixer as at least aportion of the water, and the sand stream comprising beneficial re-usesand.
 14. The system of claim 13, the ratio of two-parts water to onepart sand product is about sixty lbs of sand product and 180 lbs ofwater.
 15. The system of claim 13, wherein the extracted clay-carbonwater mix contains about ten to about eighteen percent solids, with theremaining portion comprising water.
 16. The system of claim 15, whereinthe about ten to about eighteen percent solids further comprises aboutseventy percent clay and about thirty percent carbon.
 17. A method forproducing beneficial re-use sand from foundry sand, comprising:combining sand product in a mixer; mixing water with a sand product,resulting in a sand product/water mix, the sand product received from afoundry bag-house collector or from spent foundry sand; introducing thesand product/water mix to a hydrocyclone at a pressure between about 30psi and about 35 psi; passing the sand product/water mix through thehydrocycline a single time; extracting a clay-carbon and water mix fromthe sand product/water mix, the clay-carbon and water mix re-used in afoundry; extracting wet sand from the sand product/water mix; separatingthe wet sand into a water stream and a sand stream, the water streamused as at least a portion of the water in the water and sand productmixing, and the sand stream comprising beneficial re-use sand.
 18. Themethod of claim 17, further comprising the steps of: adding about tengallons of the clay-carbon and water mix from a hydrocyclone to greensand in a muller; and producing a hydrated and activated green sand. 19.The method of claim 18, further comprising the step of passing the sandproduct/water mix through the hydrocyclone a single time.
 20. A methodfor producing beneficial re-use sand and green sand from foundry sand,comprising: combining sand product to water in a mixer; mixing waterwith a sand product at an approximate ratio of about three-parts waterto one part sand product or a smaller water to sand product ratio,resulting in a sand product/water mix, the sand product received from afoundry bag-house collector or from spent foundry sand; introducing thesand product/water mix to a hydrocyclone at a pressure between about 30psi and about 35 psi; passing the sand product/water mix through thehydrocyclone a single time; extracting a clay-carbon and water mix fromthe sand product/water mix, the clay-carbon and water mix re-used in afoundry; adding about ten gallons of the clay-carbon and water mix froma hydrocyclone to green sand in a muller; and producing a hydrated andactivated green sand; extracting wet sand from the sand product/watermix; separating the wet sand into a water stream and a sand stream, thewater stream used as at least a portion of the water in the water andsand product mixing, and the sand stream comprising beneficial re-usesand, using the beneficial re-use sand for non-foundry use.